Landry had plenty of fire and passion. He just wasn't demonstrative on the field. He didn't wear his emotions on his sleeve like Jimmy. I've actually heard several of his players talk about this and to not be fooled by his calm demeanor on the sidelines. They've seen the other side of him.
If you want to rip Garrett, I'd look for another avenue. The guy was born into a football family. It's all he knows and loves. Questioning his fire and/or passion seems foolish to me. Maybe you're right when you say he can't coach but don't tell me he doesn't have a burning desire for it and doesn't invest himself totally in that goal.
Football, Dallas Cowboys football in particular, is in his blood.
We'll settle this with a good dust up.